Life in liquids

Our most recent scientific paper highlights the survival ability of the bacteria that cause melioidosis (1).

Medical microbiology places its emphasis on the behaviour of medically-important microorganisms in conditions in and around the human body. In the clinical lab we force bacteria to grow as rapidly as we can in nutrient-rich cultures at 37’C. We only rarely use a wider range of other physical or chemical conditions and place the emphasis on environmental survival. However some bacteria are natural survivors. Burkholderia pseudomallei has been known survive for years in sterile, distilled water (2).

In our recent paper we took a look at what happened to B. pseudomallei in different types of water: distilled, tropical rain water and sea water across. We also looked at temperature range and pH, exploring physical and chemical conditions relevant to the Western Australian melioidosis outbreak in late 1997 (3). These bacteria are remarkably tough, adapting to acid pH, high temperatures and the osmotic stress of distilled water. But a part of that adaptation appears to be a change in shape. We observed bizarre forms that don’t fit neatly with the conventional description of B. pseudomallei as a Gram negative bacillus.

We also saw a modest increase in numbers while surviving in tropical rain water. B. pseudomallei caught up in clouds and deposited at a distance; something we believe may have explain the apparent movement of the WA outbreak strain NCTC 13177 500km to the East over an eight year period(4).

  1. Robertson J, Levy A, Sagripanti JL, Inglis TJ.  The survival of Burkholderia pseudomallei in liquid media.  Am J Trop Med Hyg. 2010 Jan;82(1):88-94.
  2. Wuthiekanun V, Smith MD, White NJ. Survival of Burkholderia pseudomallei in the absence of nutrients. Trans R Soc Trop Med Hyg. 1995 Sep-Oct;89(5):491.
  3. Inglis TJ, Garrow SC, Adams C, Henderson M, Mayo M. Dry-season outbreak of melioidosis in Western Australia. Lancet. 1998 Nov 14;352(9140):1600.
  4. Inglis TJ, Levy A, Merritt AJ, Hodge M, McDonald R, Woods DE. Melioidosis risk in a tropical industrial environment.  Am J Trop Med Hyg. 2009 Jan;80(1):78-84.

 

μGnome, 18-JAN-10.

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